1. Field of the Invention
The present invention relates to a liquid ejection head for ejecting liquid within liquid chamber as liquid droplets by an energy generating element, a liquid ejection apparatus, and a manufacturing method of the liquid ejection head, and in particular it relates to a technique for improving the overall adhesion force of a nozzle sheet having nozzles formed thereon.
2. Description of the Related Art
A liquid ejection apparatus represented by an inkjet printer generally includes a liquid ejection head (simply referred to as a head below) composed of a head chip having barrier layers deposited for forming a liquid chamber on a semiconductor substrate and a nozzle sheet having a number of nozzles arranged thereon. Then, by the energy generating element, liquid in the liquid chamber is ejected from the nozzle as liquid droplets. Thus, the head includes a liquid chamber part where the head chip and the nozzle sheet exist with liquid therebetween and an integrated coherent part of both members. In general, the head chip and the nozzle sheet are separately manufactured, and they are bonded together at back end steps of the head assembling.
FIG. 30 is a partial perspective view of a head 300 of such a conventional inkjet printer. In FIG. 30, for description convenience sake, a head chip 301 is exploded from a nozzle sheet 306 and they are shown in a state vertically reversed to the service condition.
Referring to FIG. 30, the head chip 301 is composed of a semiconductor substrate 302 and a barrier layer 303. That is, on the semiconductor substrate 302, heater elements 304 (energy generating elements) and also their drive circuits (not shown) depending on circumstances are formed by a photomechanical process. On the upper surface of the semiconductor substrate 302 other than vicinities of the heater elements 304, ink chambers 305 and ink passages are formed while the barrier layer 303 is deposited for bonding the nozzle sheet 306 by the same photomechanical process. On an adhesive area on the upper barrier layer 303, the nozzle sheet 306 having a number of nozzles 306a positioned according to the arrangement of the heater elements 304 is bonded to form a thermal head 300 shown in FIG. 30.
The nozzle sheet 306 is generally made of a metal, such as electrocast nickel, or a polymer film such as a polyimide film.